1. Technical Field
The present invention relates to a computer system, and more particularly, to a control method for reducing the amount of power consumed by such device by managing the storage capacity thereof.
2. Related Art
In recent years, as information technology has advanced, the amount of information used by companies, government agencies and individuals has increased dramatically. This trend has led to a demand for storage systems with much higher storage capacities.
At present, storage systems with a plurality of hard disk drives installed therein are used as storage systems to store such information, but because these hard disk drives consume a large amount of electricity, demand continues to exist for hard disk drives that consume less power.
Accordingly, a technology that partially shuts off power to hard disk drives that are not being used by the storage system has been investigated as one method by which to reduce power consumption (see JP-A-8-190762 (Patent Document 1), for example).
Furthermore, there are situations in which the original storage capacity of the storage system bought by the user is insufficient, and additional hard disk drives must be purchased. To address this situation, an on-demand service has been developed in which extra hard disk drives are included in a storage system and the user is charged for only the storage capacity used (see JP-A-2002-190762 (Patent Document 2), for example). In Patent Document 2, a technology is disclosed in which, in order to achieve a rapid increase in storage capacity, the provider of the on-demand service (i) installs and delivers to the customer both hard disk drives actually purchased by the customer and hard disk drives that were not purchased by the customer, and (ii) when the customer executes a contract to increase the storage capacity, assigns one or more of the non-purchased disk drives for use by the customer.
Incidentally, according to Patent Document 1, the power supply to hard disks that are not being used by the customer is cut off. When the customer executes a contract to increase the storage capacity, power is connected to the hard disk drives to which the power had been cut off. Here, in Patent Document 2, when additional storage capacity is to be allocated to the user, one or more logical disks are created from the previously non-powered physical disks and are assigned to the user.